How do I mount a geartooth sensor?

I only want to know which side of the black 4-pin module on the sensor has to be facing the gear on the robot. I already know how to wire it and how far away the geartooth has to be from the gear.

the side with sensor needs to face the gear (small black box)

The flat face of the sensor is what goes next to the gear. If you’re talking about the red GTS board from the Kit of Parts this year, there are mounting holes in the lexan plate of the ToughBox that put it in the proper location and orientation.

My team did not mount the gear tooth sensor in the provided holes. It seemed to require adding fairly large (3/4"+) standoffs under the board. We elected to drill holes in the opposite plate which put the gear tooth right where it needed to be. We did have to mill a little bit out of the corner of the gearbox shell to allow the circuit board some clearance.